Video apparatus and image sensing apparatus

ABSTRACT

This invention can reduce the circuit scale by synthesizing OSD data to be superposed on a picture of each resolution by using common OSD data. According to this invention, a video resolution converter converts an HD (High Definition) video signal into an SD (Standard Definition) video signal such as an NTSC or PAL video signal. A memory controller receives a sync signal identical to an SD picture obtained by frequency-dividing an HD video signal, and a sync signal based on an SD video signal, and reads out OSD data (4 bits per pixel) from the memory on the basis of these sync signals. The OSD data read out on the basis of the SD video signal is synthesized with the SD video signal by an SD_OSD_MIX unit, and then output. The OSD data read out on the basis of the SD sync signal synchronized with the HD is multiplied by an integer by an OSD resolution converter, synthesized with an HD video signal by an HD_OSD_MIX unit, and then output.

FIELD OF THE INVENTION

The present invention relates to a technique of multiplexing an OSD (OnScreen Display) on a picture when a picture is displayed on a pluralityof display devices having different display resolutions.

BACKGROUND OF THE INVENTION

A video apparatus such as a digital video camera conventionally has aplurality of display destinations, for example, as components of themain body, a liquid crystal display panel, an EVF (Electrical ViewFinder), and a line-out (e.g., an S output for transmitting a compositevideo output, or brightness and color difference signals independently)for output to an external display (e.g., a TV monitor). Video signals tobe displayed on or output to these display destinations generally havethe same resolution. The video apparatus has, e.g., a function ofswitching whether to or not to multiplex the same OSD on respectivedisplay destinations.

In terms of the video format environment, a higher-resolution Hi-Visionformat (to be referred to as an HD format hereinafter) coexists withconventional NTSC and PAL formats (to be referred to as SD formatshereinafter). Various corresponding digital formats are defined bygroups such as ITU (International Telecommunication Union) and SMPTE(Society of Motion Picture and Television Engineers).

These days, consumer digital video cameras capable of recording andplayback in both the SD and HD formats are available. Some digital videocameras can output a picture of the HD format to a display devicecapable of receiving and displaying the HD format in display, forexample, in playback in the HD format, and can also down-convert theresolution of a picture from the HD format to the SD format within theapparatus and output the picture of the SD format to a display devicecapable of receiving and displaying the SD format (e.g., Japanese PatentLaid-Open No. 2002-125193).

Under the circumstance, when different video formats are to be displayedand output, dedicated OSD data are multiplexed on the respective videoformats and displayed. Alternatively, after OSD data is multiplexed onan original picture, their resolutions are changed to display the OSDand picture. OSD data to be displayed must be prepared for eachresolution, and the quality of OSD data may be degraded.

SUMMARY OF THE INVENTION

It is an object of the present invention to provide a technique ofmultiplexing one common OSD data on video formats of differentresolutions by a simple mechanism without degrading the OSD quality.

To solve the above problem, for example, a video apparatus according tothe present invention has the following arrangement.

That is, a video apparatus which generates video signals having aplurality of resolutions comprises

-   -   a memory which stores bitmap OSD (On Screen Display) data for a        predetermined reference resolution,    -   video signal resolution conversion means for generating, from an        original video signal, video signals having different        resolutions including the reference resolution,    -   read means for reading out OSD data for each video signal by        accessing the memory in synchronism with the video signals        having the plurality of resolutions,

OSD data resolution conversion means for converting OSD data read outfor a video signal having a resolution other than the referenceresolution into OSD data having the resolution,

-   -   synthesis means, arranged for each resolution, for synthesizing        a video signal having each resolution and corresponding OSD        data, and    -   output means for outputting the video signal synthesized by the        synthesis means.

According to a preferred aspect, the resolution of OSD data ispreferably so converted as to multiply the resolution by M or 1/M (M isan integer) in the horizontal direction and by N or 1/N (N is aninteger) in the vertical direction.

Other features and advantages of the present invention will be apparentfrom the following description taken in conjunction with theaccompanying drawings, in which like reference characters designate thesame or similar parts throughout the figures thereof.

BRIEF DESCRIPTION OF THE DRAWINGS

The accompanying drawings, which are incorporated in and constitute apart of the specification, illustrate embodiments of the invention and,together with the description, serve to explain the principles of theinvention.

FIG. 1 is a block diagram showing the OSD-associated arrangement of adigital video camera according to an embodiment;

FIG. 2 is a block diagram showing a memory controller according to theembodiment;

FIG. 3 is a view showing the contents of bit assignment of output datafrom an SD color LUT and HD color LUT according to the embodiment;

FIG. 4 is a view showing an example of synthesizing OSD data on a videosignal;

FIG. 5 is a view showing the relationship between an HD display frame,NTSC display frame, and OSD data area according to the embodiment; and

FIG. 6 is a view showing the relationship between an HD display frame,PAL display frame, and OSD data area according to the embodiment.

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENT

A preferred embodiment of the present invention will be described indetail below with reference to the accompanying drawings.

<Description of Apparatus Arrangement>

FIG. 1 is a block diagram showing a video apparatus according to theembodiment. The arrangement of a digital video camera will beexemplified as the video apparatus. The image sensing resolution of thecamera unit (CCD) is a resolution of 1,920×1,080 pixels in the maximumeffective display area for HD (High Definition). The video apparatus hasa function of down-converting this resolution by a video resolutionconverter 124 to a resolution of 720×480 or 720×576 in the maximumeffective display area for the SD format (Standard Definition=NTSC orPAL format).

In FIG. 1, reference numeral 127 denotes a system controller whichcontrols the overall video apparatus and is formed from a microcomputer.

Reference numeral 101 denotes a memory controller which reads out, froma memory 102, OSD data to be-multiplexed on an SD picture down-convertedby the video resolution converter 124 in synchronism with a sync signalfrom an SD sync separation circuit 103. Similarly, the memory controller101 reads out, from the memory 102, OSD data to be multiplexed on an HDpicture selected by a video selector 123 from a camera unit 122 or CODECunit 125 in synchronism with an HD sync signal input via a frequencydividing circuit 133.

The memory 102 includes a ROM and RAM which store data, a program forimplementing various control means, and bitmap OSD data to be finallymultiplexed on an HD picture selected by the video selector 123 from thecamera unit 122 or CODEC unit 125 in the embodiment, and are also usedas a work area in order to execute control, as needed.

The SD sync separation circuit 103 separates a vertical sync signal (VD)and horizontal sync signal (HD) from an SD picture down-converted froman HD picture by the video resolution converter 124, generates a dotclock (SD_DOT_CLK) synchronized with a display pixel, and sends thesesignals to the memory controller 101 and an SD_OSD_MIX unit 105. At thisstage, the HD and SD video signals are asynchronous.

Reference numeral 104 denotes a 4-bit-input/16-bit-output SD color LUT(Look Up Table) which is formed from a RAM in order to change (write)storage data by the system controller 127. An address expressed by a4-bit input is made up of 0 to 15, each address stores 16-bit data, andthus the capacity of the SD color LUT 104 is 16×16=256 bits=32 bytes.Output 16 bits are assigned the values of a brightness Y and colordifferences Cr and Cb and how to multiplex an OSD on a picture(transparent, overwrite, simple addition, arithmetic mean, blinkpossible/impossible, or the like) (details of which will be describedlater).

In synchronism with a sync signal separated by the SD sync separationcircuit 103, the SD_OSD_MIX unit 105 multiplexes, on an SD picturedown-converted from an HD picture by the video resolution converter 124,an OSD which is based on the SD color LUT 104 and designated by OSD data(16 bits) read out from the memory 102.

Reference numeral 106 denotes a DAC (Digital Analog Converter) whichconverts a digital video signal into an analog video signal. Referencenumeral 107 denotes a liquid crystal driver which displays on a liquidcrystal display panel 108 an analog video signal converted by the DAC106. The liquid crystal display panel 108 displays OSD (On ScreenDisplay) information or the like controlled by the system controller 127on the basis of a video signal sent from the camera unit 122 via thevideo selector 123, video resolution converter 124, SD_OSD_MIX unit 105,DAC 106, and driver 107, a playback video signal from arecording/playback unit 126 via the CODEC unit 125 and video selector123, and input operation information from the user via an operation unit131 and various sensors 132 of the apparatus.

Reference numeral 109 denotes a DAC (Digital Analog Converter) which isidentical to the DAC 106. Reference numeral 110 denotes a liquid crystaldriver which drives an EVF (Electrical View Finder) 111 to display apicture. The EVF 111 performs the same display as that of the liquidcrystal display panel 108.

Reference numeral 112 denotes a DAC (Digital Analog Converter) which isidentical to the DACs 106 and 109. Reference numeral 113 denotes a 75 Ωdriver which drives an externally connected TV monitor (not shown) orthe like via a line-out connector and transmits a video signal.Reference numeral 114 denotes a line-out connector which outputs a videosignal of the NTSC or PAL format as an S signal for sending a compositesignal, or brightness and color difference signals independently.

Reference numeral 115 denotes an HD sync separation unit which separatesan HD picture selected by the video selector 123 from the camera unit122 or CODEC unit 125 into a vertical sync signal (HD_VD) and horizontalsync signal (HD_HD), generates a dot clock (HD_DOT_CLK) synchronizedwith a display pixel, and sends these signals to the frequency dividingcircuit 133 and an HD_OSD_MIX unit 118.

The frequency dividing circuit 133 outputs the input signals HD_VD,HD_HD, and HD_DOT_CLK as sync signals SD_VD′, SD_HD′, and SD_DOT_CLK′ ofthe SD format to the memory controller 101.

Reference numeral 116 denotes an OSD resolution converter whicharbitrarily multiplies, by an integer independently in the horizontaland vertical directions, OSD data read out from the memory 102 via thememory controller 101 under the control of the system controller 127.Since OSD data of the SD format is output from the memory 102, the datais multiplied by an integer in the horizontal and vertical directions togenerate OSD data of the HD format.

Reference numeral 117 denotes a 4-bit-input/16-bit-output HD color LUT(Look Up Table), similar to the SD color LUT 104. The data contents ofthe HD color LUT 117 can be changed by the system controller 127. Themeaning of each of 16 bits output from the HD color LUT 117 is the sameas that of the SD color LUT 104, and output 16 bits are assigned thevalues of the brightness Y and color differences Cr and Cb and how tomultiplex an OSD on a picture (transparent, overwrite, simple addition,arithmetic mean, blink possible/impossible, or the like) (details ofwhich will be described later).

The HD_OSD_MIX unit 118 multiplexes, on an HD picture selected by thevideo selector 123 from the camera unit 122 or CODEC unit 125, an OSDwhich is based on the HD color LUT 117 and designated by OSD dataprepared by arbitrarily multiplexing OSD data read out from the memory102 by the OSD resolution converter 116 independently in the horizontaland vertical directions in synchronism with a sync signal separated bythe HD sync separation unit 115.

Reference numeral 119 denotes a DAC (Digital Analog Converter) having ahigh-speed conversion characteristic capable of DA conversion up todisplay of an HD resolution. Reference numeral 120 denotes a 75 Ω driverwhich drives an external HD-compatible monitor (not shown) or the likeconnected to the D terminal and transmits a video signal. Referencenumeral 121 denotes a D terminal connector which is based on “CP-4120:Interface Between a Digital Tuner and Television Receiver usingD-Connector” established by JEITA (Japan Electronics and InformationTechnology Industries Association), and connects an external TV monitor(not shown) or the like by separately using a D terminal cable (notshown).

The camera unit 122 includes a lens, CCD (Charge Coupled Device), andother peripheral circuits and functions necessary for image sensing, andcan take an HD picture.

The video selector 123 selects a video signal from the camera unit 122or CODEC unit 125 under the control of the system controller 127.

The video resolution converter 124 has a function of down-converting anHD picture from the camera unit into an SD picture.

The CODEC unit 125 MPEG2-encodes an HD video signal on the basis of theMPEG2 (Moving Picture Experts Group 2) format, and sends the encodedsignal to the recording/playback unit 126 to record the data on arecording medium (not shown). In playback, recorded data is read outfrom a recording medium (not shown) by the recording/playback unit 126,and the CODEC unit MPEG2-decodes the data and sends it to the videoselector 123.

The recording/playback unit 126 records video data encoded by the CODECunit 125 on a recording medium (not shown) such as a magnetic tape,optical disk, or HDD. In playback, the recording/playback unit 126 readsout encoded video data from the recording medium, and transfers the datato the CODEC unit 125.

The system controller 127 controls the whole apparatus, and is connectedto the operation unit 131 (instruction switches such as a recordingbutton, playback button, and fast-forward button) to be operated by theuser, and various sensors 132 (remaining battery amount sensor,recording medium presence/absence sensor, timer, and the like). Thesystem controller 127 switches between photographing and playback, andin addition, writes in the memory 102 via the memory controller 101 OSDdata (one pixel=4 bits) to be properly superposed and displayed on aphotographed picture.

<Memory Controller 101>

FIG. 2 shows the block arrangement of the memory controller 101 and therelationship with the memory 102 according to the embodiment. The videoapparatus according to the embodiment outputs a video signal of NTSC(720×480 pixels) as the SD format and a video signal of 1,920×1,080pixels as the HD format.

In this case, the memory 102 according to the embodiment has a capacityof NH×NV pixels in the horizontal and vertical directions for 4 bits perpixel. NH and NV are smaller in size than the SD format, and when theyare multiplied by an integer, the products do not exceed the size of theHD format. For example, NH=600 and NV=400.

The memory controller 101 is formed from address generation circuits 400and 401, and an address bus arbitration circuit 402.

The address generation circuit 400 generates address signals in theraster scan order in order to read out OSD data from the memory 102 onthe basis of sync signals SD_VD, SD_HD, and SD_DOT_CLK generated by theSD sync separation circuit 103.

The address generation circuit 401 generates similar address signals onthe basis of the sync signals SD_VD′, SD_HD′, and SD_DOT_CLK′ outputfrom the frequency dividing circuit 133. Since the frequency dividingcircuit 133 generates a sync signal of the SD format on the basis of async signal of the HD format from the HD sync separation unit 115, theaddress generation circuit 401 generates an OSD data read address to beoutput from the D terminal connector 121.

The address bus arbitration circuit 402 performs write/read of OSDbitmap data in/from the memory 102 by the system controller 127, andaddress arbitration between the two address generation circuits 400 and401. Readout OSD data is data of a resolution corresponding to the SDformat, and provides only a small display in the HD format. To preventthis, the OSD resolution converter 116 also multiplies OSD data to beoutput with the HD format by an integer (two times in the embodiment) inboth the horizontal and vertical directions, and then outputs the OSDdata.

Note that recent memories can access at several hundred M clocks, and aband enough to read OSD data is ensured for the address bus arbitrationcircuit 402 and memory 102. Hence, even while OSD data for OSD displayare read out from the address generation circuits 400 and 401, thesystem controller 127 can write OSD data to be displayed in the memory102.

<Description of LUT>

As described above, OSD data of one pixel read out from the memory 102is formed from 4 bits. The 4-bit data is decoded into 16-bit data by theSD color LUT 104 and HD color LUT 117, respectively, and video data andthe OSD data are synthesized by the OSD_MIX units 105 and 118,respectively.

Each of 16 bits is assigned a meaning as shown in FIG. 3. The MSB (bit15) represents which of a sensed picture or playback picture (to besimply referred to as sensed data hereinafter) and OSD data is passed.To pass sensed data, bit 14 and lower bits are insignificant. In otherwords, the following description applies only when at least OSD data isdisplayed.

Bit 14 represents which of a simple OSD or the arithmetic mean of videodata and OSD data is displayed. If the simple OSD is set, acorresponding pixel displays only the OSD. For the arithmetic mean, theOSD and sensed picture are mixed by 50% each, and a sensed image isdisplayed through the OSD.

Bit 13 represents whether to or not to blink the display.

Bits 9 to 12 represent “reserved”, and bits 0 to 7 store Y, Cb, and Crdata.

To display an OSD of the photographing month, date, and time, and theremaining battery amount, as shown in FIG. 4, the system controller 127writes in the memory 102 the character pattern of the photographingmonth, date, and time, and a symbol pattern representing the remainingbattery amount. At this time, data as shown in FIG. 3 are written ataddresses 0 to 15 of the SD color look-up table 104, and the display canbe provided with a desired color and desired form.

Similarly, an OSD of the HD format can be displayed by writing the samedata in the HD color LUT 117.

As is apparent from the above description, when the MSB in 16-bit dataof all addresses 0 to 15 in the HD color LUT 117 is so set as to passvideo data, an OSD is displayed on the liquid crystal display panel 108and the like, but only video data can be displayed on an HD-compatibledisplay device connected to the D terminal.

That is, color LUTs are respectively arranged for the SD and HD formats,and the corresponding OSD_MIX units 105 and 118 independently execute aprocess of displaying an OSD. The display color and display effect canbe independently set while one OSD data is shared. Since video data tobe finally displayed is synthesized with an OSD immediately beforeoutputting the video data, degradation of the OSD quality can beprevented.

<Relationship with Display Frame>

The relationship between an HD display frame, an SD display frame, anddisplay of multiplexed OSD data will be explained with reference to FIG.5.

In FIG. 5, reference numeral 201 denotes a full resolution of1,920×1,080 (horizontal 1,920 pixels×vertical 1,080 lines/frame) in theHD effective display area. The display is an interlaced display, and theresolution is 1,920×540 per field (1,920×1,080 per frame).

Reference numeral 202 denotes an effective display area of an HDdisplay-compatible display device. The resolution of the effectivedisplay area changes depending on the use of various televisionmonitors. One criterion of the resolution is about 85% of the effectivedisplay area 201.

Reference numeral 203 denotes an SD-NTSC full resolution of 720×480(horizontal 720 pixels×vertical 480 lines/frame) when an OSD ismultiplexed while the SD resolution is kept unchanged. Since the displayis an interlaced display, the field size is 720×240.

Reference numeral 204 denotes an OSD AREA image area prepared bydefining within the SD-NTSC full resolution 203 an area for multiplexingan OSD so as to fully display an OSD. Assuming that the size of the OSDAREA image area is NH×NV (horizontal NH pixels×vertical NV lines/frame),NH and NV are integers, and NH≦720 and NV≦480.

Reference numeral 205 denotes an SD-NTSC (×2) resolution of 1,440×960(horizontal 1,440 pixels×vertical 960 lines/frame) obtained by doublingthe SD-NTSC full resolution 203 in both the horizontal and verticaldirections.

Reference numeral 206 denotes an OSD AREA (×2) resolution of 2NH×2NV(horizontal 2NH pixels×vertical 2NV lines/frame) obtained by doublingthe OSD AREA image area 204 in both the horizontal and verticaldirections.

In order to display common OSD data in both the SD display and HDdisplay without any omission, the embodiment sets2NH≦1,440, 2NV≦960The above-mentioned resolution of 600×400 satisfies this condition.

An example of employing NTSC as the SD format has been described, and anapplication of the PAL format is shown in FIG. 6.

The PAL format is different in size from the NTSC format of FIG. 5. Itshould be noted that the display exceeds the HD full resolution area 201when an SD-PAL full resolution area 303 is doubled in both thehorizontal and vertical directions. Hence, PH and PV are determined sothat an area 306 prepared by doubling an OSD area 304 falls within therange of an effective display area 302 of an HD display-compatibledisplay device. These settings do not pose any problem inOSD-multiplexed display according to the embodiment. Also in this case,for example, PH=600 and PV=400 satisfy this condition.

The video apparatus of the embodiment independently converts theresolutions of a picture and OSD data to be multiplexed on the picture,and then multiplexes the picture and OSD data. The video apparatus cantherefore multiplex and display, from common OSD data, OSD data whosedisplay color can also be independently controlled within the effectivedisplay area, on a plurality of pictures which are generated from thesame original picture but have different resolutions, without degradingthe qualities of these pictures. That is, a conventional apparatus mustprepare different OSD data to be multiplexed on pictures of differentresolutions, whereas the video apparatus of the embodiment suffices toprepare only single OSD data, reducing the circuit scale in ASICimplementation. Also, degradation of the ODS display quality uponconversion of the resolution can be prevented by converting the OSDresolution by an integer multiple.

The embodiment has exemplified NTSC and HD, and PAL and HD, but thepresent invention can be applied to an apparatus having three, NTSC,PAL, and HD display functions. In the embodiment, a video signal of theSD format is common to the liquid crystal display panel, EVF, andline-out connector. However, the liquid crystal display panel and EVFare permanently provided to the apparatus, and thus need not have thesame resolution as that of an output from the line-out connector. Thatis, the embodiment has exemplified two resolutions, but three or moreresolutions may be adopted.

As has been described above, the present invention can reduce thecircuit scale by synthesizing OSD data to be superposed on a picture ofeach resolution by using common OSD data. The present invention canprevent degradation of the quality upon conversion of the resolution byconverting the resolution of OSD data by an integer multiple.

As many apparently widely different embodiments of the present inventioncan be made without departing from the spirit and scope thereof, it isto be understood that the invention is not limited to the specificembodiments thereof except as defined in the claims.

CLAIM OF PRIORITY

This application claims priority from Japanese Patent Application No.2004-145487 filed May 14, 2004, which is hereby incorporated byreference herein.

1. A video apparatus which generates video signals having a plurality ofresolutions, comprising: a memory which stores bitmap OSD (On ScreenDisplay) data for a predetermined reference resolution; video signalresolution conversion means for generating, from an original videosignal, video signals having different resolutions including thereference resolution; read means for reading out OSD data for each videosignal by accessing said memory in synchronism with the video signalshaving the plurality of resolutions; OSD data resolution conversionmeans for converting OSD data read out for a video signal having aresolution other than the reference resolution into OSD data having theresolution; synthesis means, arranged for each resolution, forsynthesizing a video signal having each resolution and corresponding OSDdata; and output means for outputting the video signal synthesized bysaid synthesis means.
 2. The apparatus according to claim 1, whereinsaid OSD data resolution conversion means multiplies OSD data read outfrom said memory by M or 1/M (M is an integer) in both horizontal andvertical directions.
 3. The apparatus according to claim 1, wherein saidOSD data resolution conversion means converts OSD data so as to set anarea size of resolution-converted OSD data to be smaller than an areasize of a picture having a corresponding resolution.
 4. The apparatusaccording to claim 1, wherein said synthesis means has, for eachresolution, a look-up table which receives, as an address, OSD data readout from said memory and outputs data for determining an OSD displayform.
 5. The apparatus according to claim 3, wherein the look-up tableis writable, and stores mixing of at least a video signal and OSD data,display of video data without displaying OSD data/display of OSD datawithout displaying video data, and color data.
 6. The apparatusaccording to claim 1, wherein said memory stores OSD data having thelowest resolution among the plurality of resolutions.
 7. The apparatusaccording to claim 6, wherein letting WO×HO be a display area size ofthe OSD data having the lowest resolution, and Wi×Hi be a display areasize of each resolution other than the lowest resolution,WO×N<WiHO×M<Hi (where N and M are integers)
 8. An image sensing apparatuscomprising a video apparatus defined in claim
 1. 9. A video apparatuswhich generates video signals having a plurality of resolutions,comprising: an imaging device performs image sensing operation andgenerates a video signal having a predetermined resolution; a videosignal resolution converter generates, from the video signal suppliedfrom said imaging device, at least one video signal having differentresolutions; a memory which stores bitmap OSD (On Screen Display) datacommon to a plurality of resolutions; a plurality of synthesis circuitssynthesizes each of the video signal having the predetermined resolutionand the video signal having the different resolution with the OSD dataread out from said memory; and an OSD data resolution converter, whichis interposed between at least one of said plurality of synthesiscircuits and said memory, converts the resolution of the OSD data readout from said memory.